Analysis of Diaphragmatic Motion with Prone Positioning Using Dynamic MRI

Tomita, Kazuhide; Sakai, Yasutomo; Monma, Masahiko; Ohse, Hirotaka; Imura, Shigeyuki

doi:10.1589/jpts.16.85

Cited by 9 publications

(10 citation statements)

References 13 publications

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“…No statistically significant difference was found between the baseline values of FVC sitting and FVC supine; however, in such a small sample, this standalone finding is insufficient to confirm their equivalence. The finding should, therefore, be taken together with literature reports of the equivalence of FVC between the two positions ( 18 , 22 ).…”

Section: Discussionmentioning

confidence: 80%

“…Broadly speaking, after automatic segmentation of the lung cross-sectional area (CSA) on each frame, three 1-D lung length measures are computed—one at the anterior chest wall margin, one at the tracheal bifurcation point, and one at the posterior chest wall margin (denoted ANT, CNT, and PST, respectively), as well as the diaphragm length (DIA). The lung length measurements, which reflect diaphragm movement, are summed together to provide an estimate of the total distance of motion (TDM) of the diaphragm ( 16 , 18 ). The DIA is computed as described in the caption of Figure 2 .…”

Section: Methodsmentioning

confidence: 99%

“…Exploratory MRI endpoints derived from temporal profiles of lung and diaphragm measurements were investigated in both healthy controls and non-ambulant DMD boys. To enable this, we extended previous and similar work that has used proton ( 1 H) MRI to assess pulmonary function in healthy volunteers ( 14 – 18 ).…”

Section: Introductionmentioning

confidence: 99%

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Semi-Automated Analysis of Diaphragmatic Motion with Dynamic Magnetic Resonance Imaging in Healthy Controls and Non-Ambulant Subjects with Duchenne Muscular Dystrophy

et al. 2018

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Subjects with Duchenne Muscular Dystrophy (DMD) suffer from progressive muscle damage leading to diaphragmatic weakness that ultimately requires ventilation. Emerging treatments have generated interest in better characterizing the natural history of respiratory impairment in DMD and responses to therapy. Dynamic (cine) Magnetic Resonance Imaging (MRI) may provide a more sensitive measure of diaphragm function in DMD than the commonly used spirometry. This study presents an analysis pipeline for measuring parameters of diaphragmatic motion from dynamic MRI and its application to investigate MRI measures of respiratory function in both healthy controls and non-ambulant DMD boys. We scanned 13 non-ambulant DMD boys and 10 age-matched healthy male volunteers at baseline, with a subset (n = 10, 10, 8) of the DMD subjects also assessed 3, 6, and 12 months later. Spirometry-derived metrics including forced vital capacity were recorded. The MRI-derived measures included the lung cross-sectional area (CSA), the anterior, central, and posterior lung lengths in the sagittal imaging plane, and the diaphragm length over the time-course of the dynamic MRI. Regression analyses demonstrated strong linear correlations between lung CSA and the length measures over the respiratory cycle, with a reduction of these correlations in DMD, and diaphragmatic motions that contribute less efficiently to changing lung capacity in DMD. MRI measures of pulmonary function were reduced in DMD, controlling for height differences between the groups: at maximal inhalation, the maximum CSA and the total distance of motion of the diaphragm were 45% and 37% smaller. MRI measures of pulmonary function were correlated with spirometry data and showed relationships with disease progression surrogates of age and months non-ambulatory, suggesting that they provide clinically meaningful information. Changes in the MRI measures over 12 months were consistent with weakening of diaphragmatic and inter-costal muscles and progressive diaphragm dysfunction. In contrast, longitudinal changes were not seen in conventional spirometry measures during the same period. Dynamic MRI measures of thoracic muscle and pulmonary function are, therefore, believed to detect meaningful differences between healthy controls and DMD and may be sensitive to changes in function over relatively short periods of follow-up in non-ambulant boys with DMD.

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Section: Discussionmentioning

confidence: 80%

Section: Methodsmentioning

confidence: 99%

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Semi-Automated Analysis of Diaphragmatic Motion with Dynamic Magnetic Resonance Imaging in Healthy Controls and Non-Ambulant Subjects with Duchenne Muscular Dystrophy

et al. 2018

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“…Since the first reports of early mobilization for mechanically ventilated patients were published in the mid-2000s, the literature on the effectiveness, feasibility, and safety of early mobilization has grown substantially 21 , 22 , 23 ) . In addition, fundamental studies on physiological changes in respiratory function associated with physiotherapy have provided insight on new ways to improve the care and management of mechanically ventilated patients 24 , 25 , 26 , 27 ) . Respiratory physiotherapy techniques used for mechanically ventilated patients are divided into three activities: mobilization, chest physiotherapy, and muscle retraining 23 , 28 ) .…”

Section: Discussionmentioning

confidence: 99%

Effect of early mobilization on discharge disposition of mechanically ventilated patients

et al. 2015

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[Purpose] The purpose of this study was to clarify the benefits of early mobilization for mechanically ventilated patients for their survival to discharge to home from the hospital. [Subjects and Methods] Medical records were retrospectively analyzed of patients who satisfied the following criteria: age ≥ 18 years; performance status 0–2 and independent living at their home before admission; mechanical ventilation for more than 48 h; and survival after mechanical ventilation. Mechanically ventilated patients in the early mobilization (EM) group (n = 48) received mobilization therapy, limb exercise and chest physiotherapy, whereas those in the control group (n = 60) received bed rest alone. Univariate and multivariate logistic regression analyses were performed to identify clinical variables associated with discharge disposition. [Results] Early mobilization was a positive independent factor and the presence of neurological deficits was a negative factor contributing to discharge to home. Among patients surviving mechanical ventilation without neurological deficits, the rate of discharge to home was significantly higher among patients in the EM group that in the control group (76% vs. 40%). [Conclusion] Early mobilization can improve the rate of discharge to home of patients requiring mechanical ventilation because of non-neurological deficits.

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“…The most commonly used positions are the supine, prone, side-lying (SL), semi-prone (Sim’s position [SP]), and sitting positions. Many reports have described changes in the regional distribution of ventilation in the supine, prone, SL, and erect positions 3 , 4 , 5 ) . However, the regional distribution of ventilation in SP has not been clarified.…”

Section: Introductionmentioning

confidence: 99%

Regional lung volume differences between the side-lying and semi-prone positions

et al. 2016

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[Purpose] This study aimed to clarify the differences in regional lung volume between the semi-prone (Sim’s position) and side-lying position, and the optimal position for increasing lung volume. [Methods] Measurements were performed in both positions on both sides. Sim’s position was inclined 45° forward from the side-lying position. A 1.5-T system with a fast advanced spin-echo sequence in the coronal plane was used for magnetic resonance imaging. [Results] The two positions did not significantly differ in total lung capacity and its subdivisions on both sides, except the left lung in the right side-lying position and right Sim’s position. In the nondependent lung, the percentage lung volume of the dorsal segment was significantly higher in the right Sim’s position than in the right side-lying position. However, no significant difference was observed between the left side-lying and left Sim’s position. [Conclusion] The heart was displaced ventrally by gravity in Sim’s position and leaned on the ventral parapet. The spaces for the expansion of the ventral and dorsal segments of the lung were decreased and increased in Sim’s position, respectively. With a nondependent left lung, the increase in the percentage lung volume of the dorsal segment was greater in Sim’s position than in the side-lying position.

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Analysis of Diaphragmatic Motion with Prone Positioning Using Dynamic MRI

Cited by 9 publications

References 13 publications

Semi-Automated Analysis of Diaphragmatic Motion with Dynamic Magnetic Resonance Imaging in Healthy Controls and Non-Ambulant Subjects with Duchenne Muscular Dystrophy

Semi-Automated Analysis of Diaphragmatic Motion with Dynamic Magnetic Resonance Imaging in Healthy Controls and Non-Ambulant Subjects with Duchenne Muscular Dystrophy

Effect of early mobilization on discharge disposition of mechanically ventilated patients

Regional lung volume differences between the side-lying and semi-prone positions

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